Evaporator for refrigerating machines



May 17, 1938. c. sTEl-:NsTRUP EVAPORATOR FOR REFRIGERATING MACHINESFiled Aug. 29, 1956 3 3 r \\l \\H/ \\I|Ml/ \\l/ l/ T Q 4 Z. n \J A y/Attorney.

Patented May i1, 193s 2,112,861

AUNITED STATES PATENT OFFICE cin-nnen Steenstrup, Schenectady, N. y.,aeslgnor to General Electric Company, a corporation of New York'Application August 29, 1936, Serial No. 98,456

3 Claims. (Cl. 62-126) My invention relates to evaporators or cooling acylindrical header 20 from which it is withunits for refrigeratingmachines. drawn through a suction conduit 2l and is re- It is an objectof my invention to provide an turned to the casing I4. 'I'his cycle ofoperation improved evaporator of the flooded type for recontinues aslong as thecompressor Within the 5 frigerating machines, having a headerand a plucasing is operating. The temperature within the 5 rality ofU-shaped depending refrigerant clrcucompartment II is regulatedthermostatically in lating passages and having an improved arrangetheusual manner by controlling the operation ment for providing a rapid andefficient positive of the motor which drives the compressor Withincirculation of liquid refrigerant through the pasthe casing I4. sagesthereof. In evaporators of the flooded type it is desir- 10 Anotherobject of my invention is to provide an able to provide some arrangementfor producing improved evaporator of the flooded type for rea rapidcirculation of liquid refrigerant and a frigerating machines which shallprovide a posirecirculation of liquid refrigerant from the header tiveand eicient circulation of liquid refrigerant through the refrigerantcirculating passages. An with a minimum of turbulence within the header.increased rate of circulation of liquid refrigerant 15 Further objectsand advantages of my invenincreases the rate of absorption of heat and,contion will become apparent as the following desequently, provides anevaporator which will cool scription proceeds, and the features ofnovelty the surrounding air more lrapidly and will also whichcharacterize my invention will be pointprovide for rapid freezing ofwater, desserts and zo ed out with partioularity in the ciaims annexedto the like. I attain these advantages by constructand forming a part ofthis specification. ing the evaporator of two sheets of metal having Fora better understanding of my invention, indentations formed therein toprovide a header reference may be had to the accompanying drawand aplurality of depending U-shaped refriging in which Fig. 1 shows ahousehold refrigerator erant circulating passages or conduits and an arutilizing an evaporator embodying my invention; rangement whereby therefrigerant supplied to 25 Fig. 2 is an enlarged perspective view of thethe evaporator is utilized to produce a positive evaporator shown inFig. 1; and Fig. 3 is a plan circulation of liquid refrigerant to theheader and view of the sheet metal portions of the evaporator arecirculation from the header in a predetershown in Fig. 1 prior tobending. mined direction. Portions of the U-shaped reso Referring now tothe drawing, in Fig. 1 I have frigerant passages are preferably arrangedin 3o shown a household refrigerator comprising a a horizontal plane toprovide a surface for Supcabinet iu having a food compartment Il and aporting freezing trays which afford rapid freezdoor I2 for closing thecompartment. The coming 0f Water, desserts and the like. partment II iscooled by an evaporator or cooling Referring 110W t0 Fig. 2, theevaporator I3 iS unit I3 arranged in the upper portion thereof and madeof inner and outer sheet metal portions 22 35 supplied with refrigerantfrom a refrigerating and 23 respectively. The Sheets 22 and 23 aremachine mounted on the top of the cabinet. The made of stainless steelor other suitable material refrigerating machine comprises a closedcasand are provided With indentatOnS 01 Corrugaing I4 in which isarranged a motor and a retions forming the cylindrical header 20adjacent 40 frigerant compressor, an air cooled refrigerant the upperendS 0f the Sheets, a plurality 0f 40 condenser I5 comprising a conduitI6 and a float separate U-shaped depending conduits 25, a valve chamberI'I. During the operation of the sinuous conduit 26, a mallfOld 2l and aplurality motor and compressor within the casing I I of ducts 28connected to the manifold 2l and the gaseous refrigerant is compressedand discharged lower portions of the U-shaped passages 25. The into theconduit I6 of the condenser I5 where upper ends of the U-shaped passagesall com- 45 it is cooled by air circulating over the condenser municatewith the lower portions of the header due to the natural drafts, and isliquefied. The 20 and are all arranged Substantially in 10I1giliquefiedrefrigerant then ows through a contudinal allnement. The sheets 22 and23 are nection I8 to the float valve chamber I'I. When bent to form sidewalls 29 and 30 and top and a. predetermined amount of liquidrefrigerant has bottom Walls 3l and 32 respectively, providing 50collected in the chamber I1 a float arranged upper and lower surfacesBla and 32a for suptherein rises and admits refrigerant to theevapoporting freezing trays and the like. Depending rator I3 through aconduit I9. The liquid re- U-shaped refrigerant circulating passages 25exfrigerant is vaporized by the absorption of heat tend downwardly fromthe header 20 within the from the chamber II and the vapor collects inside wall 29 and across the bottom wall 32, and 55 the sinuous conduit26 extends in part across the top wall 3| and in part within the sidewall 30.

The sheets 22 and 23 are secured together around their edges and betweenthe indentations by welding, brazing or any other suitable manner; thefront and rear edges of the sheet 22 being folded over the respectiveedges of the sheet 23 in the manner indicated at 24. A flange 33 formedon the sheet 22 at the end thereof remote from the header 20 fitsagainst the side wall 29 and is welded or otherwise secured thereto. Ametal sheet 34 is welded to the upper end of the side wall 30 andconstitutes a side wall for an upper freezing chamber. The wall 29 andthe wall 3l are provided with flanges 35 and 36 respectively, forsecuring the evaporator to a removable top wall of a refrigeratorcabinet. The ,general arrangement of the header and the passages withinthe wall of the evaporator is not my invention but is the invention ofLeonard W. Atchison, and is disclosed and claimed in his copendingapplication, Serial No. 51,846, led November 27, 1935, and assigned toGeneral Electric Company, the assignee of my present invention, I donot, therefore, herein claim any invention claimed in the said Atchisonapplication.

Referring now to Figs. 2 and 3, liquid refrigerant is admitted to theevaporator I3 through the conduit I9 and enters a passage 31 formed inthe side wall 29 and the bottom wall 32. 'Ihe passage 31 communicatesdirectly with the sinuous passage 26 and the refrigerant therefore flowsinto the sinuous passage, circulates therethrough and ows to themanifold 21.

The ducts 28 which convey the refrigerant uniformly from the manifold 21to the several U-shaped passages 25 are arranged .in such manner as toinduce a positive circulation of liquid refrigerant in a predetermineddirection through each of the U-shaped passages. In order to accomplishthis mode of circulation each of the ducts 28 is arranged to injectrefrigerant directly and longitudinally into one leg of a U-shapedpassage, to produce a flow through that leg of the passage and upwardlyto the header 20. 'I'he resultant injector action produces a positiveflow of liquid refrigerant through each of the U-shaped passages, liquidrefrigerant recirculating from the header downwardly through the otherleg of the passage; a rapid circulation and recirculation in allU-shaped passages is thereby provided. In order to minimize theturbulence of the liquid refrigerant within the header 20 which resultsfrom the rapid circulation of refrigerant, I arrange the injectors 28 sothat the same direction of flow of liquid refrigerant obtains inadjacent legs of adjacent U-shaped conduits. It is evident that when therefrigerant is thus caused to circulate in the same direction in thepairs of adjacent legs of the U-shaped passages, there will be a lessfrequent reversal of the direction of flow of refrigerant along theheader. If the direction of flow were made thev same in al1 the U-shapedpassages, each passage would have refrigerant flowing therein in adirection opposite the direction of flow in the adjacent passage andthere would be increased turbulence and consequently increasedresistance to the circulation of liquid refrigerant. In the evaporator,as described above, there will be larger areas of upward and downwardflow, since each, area will correspond to the portion of the headerabove two of the legs of the U-shaped passages.

Dun'ng the operation of the evaporator described above, refrigerant isadmitted to the passage 31 from the passage I9 and ows from the in thechamber Il and from articles placed on the freezing shelf 31a; Thevaporized and liquid refrigerant flows fromf the manifold 21 insubstantially equal amounts through the ducts 23 and into the severalU-shaped passages 25. Since each of the ducts 28 directs refrigerantupwardly into only one leg of the U-shaped passage with which itcommunicates, the direction of flow of refrigerant in each U-shapedpassage is definitely predetermined and minimum turbulence of liquid-refrigerant in the header is assured at all times. Liquid refrigerantvaporized within the passages 25 by the absorption of heat from articlesresting on the shelf 32a and from the air within the chamber Il,collects in the header and is withdrawn therefrom through suctionconduit 2l.

It will be apparent from the foregoing that I have provided a floodedevaporator of simple construction having an improved arrangement forpredetermining the direction of ow of refrigerant in the circulatingpassages thereof and for assuring a minimum of turbulence and,therefore, a minimum resistance to circulation of the liquidrefrigerant.

While I have described my invention in connection with a householdrefrigerator, other applications will readily be apparent to thoseskilled in the art. Ido not, therefore, desire my invention to belimited to the particular construction shown and described, and I intendin the appended claims to cover all modifications within the spirit andscope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A flooded evaporator for refrigerating machines comprising a headerand a plurality of separate depending U-shaped refrigerant circulatingpassages, both of the ends of each of said passages communicating withsaid header and all of the ends of said passages being substantially inlongitudinal alinement along said header, means including a plurality ofducts one communicating with the lower portion of each of said U-shapedpassages and injecting liquid refrigerant longitudinally into saidU-shaped passages for producing a circulation of liquid refrigeranttoward said header in one leg of each of said passages and away fromsaid header in the other leg of each of said passages and fordetermining the direction of circulation of liquid refrigerant in eachof said passages, and means for withdrawing gaseous refrigerant fromsaid header.

2. A flooded evaporator for refrigerating machines comprising a headerand a plurality of separate depending U-shaped refrigerant circulatingpassages, both of the ends of each of said U-shaped passagescommunicating with said header and all of the ends of said U-shapedpassages being substantially in longitudinal alinement along saidheader, means including a plurality of ducts of relatively smallcross-sectional area as compared with the cross-sectional area of saidpassages and injecting liquid refrigerant longitudinally into one leg ofeach of said passages for producing a circulation of liquid refrigeranttoward said header through said one leg and away from said header in theother of said legs, and means for withdrawing gaseous refrigerant fromsaid header.

3. A flooded evaporator for refrigerating machines comprising a headerand a plurality of separate depending U-shaped refrigerant circulatingpassages, both of the ends of each of said passages communicating withsaid header and all of the ends of said passages being substantially inlongitudinal alinement along said header, means communicating with thelower portion of each of said U-shaped passages and injecting liquidrefrigerant longitudinally into said U-shaped passages for producing acirculation of liquid refrigerant toward said header in one of the legsof each of said passages and away from said header in the other leg ofeach of said passages and for determining the direction of circulationof liquid refrigerant in each of said passages, said circulationproducing means being arranged to circulate the liquid refrigerant inthe same direction in adjacent legs of adjacent ones of said U-shapedpassages,

and means for withdrawing gaseous refrigerant 10 from said header.

CHRIS'I'IAN S'I'EENS'I'RUP.

